Respectfully, I disagree. To the point where I want to yell at the screen. If the appliance still works, don’t stop supporting it. 9 years is not that long of a time.
I don’t care that it means more work for the development team. They had software working for it, and at its core YouTube is just displaying streaming video. If it can work on a $15 Roku stick, it can run on an Apple TV of any flavor.
Please stop perpetuating all this BS that we should be replacing our perfectly functional hardware every 5 years and keep software working.